XSB Src (SVN)-old

final change

Added thread contexts for MT engine.

Fixing the fix.

Hush little compiler
Life aint terrible
I just removed
An unused variable.

Several updates/refinements to lib predicates:
assoc_xsb.P: added priority queue implementation
ora_call.H: cleaned up import
proc_files: Added 'quiet' option (and preliminary, non-working, json support)
prolog_db: Change $VAR to _$Var$ to avoid collisions (should be a better way..)
Also added a couple of new predicates, including gdb and sgdb to
get and update a global containing a (interned) PDB.

xwam changes due to changes in compiler.

Added more builtins to be compiled to the builtin instruction.
Updated variable processing to better process non-first but not last
occurrences of variables.
Added processing of more builtin instruction forms, and released registers
when allowed after calling builtin instructions.
Rest are xwam changes due to compiler changes.

b64_dec now accepts list(Var) as output spec

added a check that inpput to b64_dec must be a string.
Fixed a typo in an abort in base64.P

Changed some imports from usermod to correct places.